Electronic device

ABSTRACT

A novel electronic device including a flexible display is presented. The electronic device has a flexible display including an organic light emission diodes and a plurality of columnar bodies linked together. Users can transform the shape of the electronic device into a tablet, an eBook, or a hand-held gaming device. The electronic device is configured to resize its main display area in accordance with the selected mode.

TECHNICAL FIELD

This disclosure is related to electronic devices.

BACKGROUND ART

A variety of types of electronic devices having flexible displays havebeen proposed (see Patent Documents 1 and 2, for example).

REFERENCE Patent Document

-   [Patent Document 1] U.S. Pat. No. 8,427,420-   [Patent Document 2] United States Patent Application Publication No.    2014/0028597

DISCLOSURE OF INVENTION

Any novel one of circuits, architectures, driving methods, andelectronic devices related to or having display devices is provided inthis disclosure.

Specifically, an electronic device that includes a flexible displayincluding a device layer and a plurality of columnar bodies is provided,but one embodiment of the invention is not limited thereto. Theelectronic device may have the following features. That is, each of theplurality of columnar bodies is mechanically or physically linked withneighboring one or two of the columnar bodies at a link portion androtatable around an axis at the link portion. The flexible display isdesigned to change its shape in accordance with a shape formed by theplurality of columnar bodies. The flexible display is configured to showa first display area. A grip can be formed by rolling at least one of aright side and a left side of the electronic device, by rotating some ofthe plurality of columnar bodies around the axes at the link portions. Aportion of the flexible display corresponding to the grip is designed tobe located between a hand of a user and the plurality of columnar bodiesthat constitute the grip when the user holds the grip. The first displayarea is configured to be resized when the grip is formed. Furthermore,the flexible display may be configured to show a second display area inthe grip. Furthermore, an angle formed by neighboring columnar bodiesmay be limited by a stop provided for each of the columnar bodies.Furthermore, the electronic device may be configured to show a firstimage at a first portion of the first display area and a second imagefor controlling the first image at a second portion of the first displayarea when both the right side and the left side of the electronic deviceare rolled. Furthermore, the electronic device may be designed to beprevented from being folded by a plate provided through two or more ofthe columnar bodies. Furthermore, the device layer may include organiclight emission diodes (OLEDs) and circuits for controlling the OLEDs.Furthermore, the flexible display may include an elastic material.

Users can easily transform the shape of the electronic device as atablet, an eBook or a hand-held gaming device. The electronic device isconfigured to change the size of its main display area and to arrange orprovide buttons for operation, in accordance with the shape. Forexample, holding the electronic device comfortably with one hand andreading a newspaper on the electronic device while holding a cup withthe other hand (eBook mode), or holding the electronic device with bothhands like a hand-held gaming device (game mode), which allows morecomfortable and stable grip of the electronic device while playing agame, in addition to using the electronic device as a normal tabletdevice (tablet mode), is possible with one device.

BRIEF DESCRIPTION OF DRAWINGS

In the accompanying drawings:

FIGS. 1A to 1C show examples for explaining an electronic device;

FIGS. 2A to 2C show examples for explaining an electronic device;

FIGS. 3A to 3C show examples for explaining an electronic device;

FIGS. 4A to 4C show examples for explaining an electronic device;

FIGS. 5A to 5D show examples for explaining an electronic device;

FIGS. 6A to 6D show examples for explaining an electronic device;

FIGS. 7A to 7D show examples for explaining an electronic device;

FIGS. 8A to 8C show examples for explaining an electronic device;

FIGS. 9A to 9C show examples for explaining an electronic device;

FIGS. 10A to 10C show examples for explaining an electronic device;

FIG. 11 shows an example for explaining an electronic device;

FIG. 12 shows an example for explaining an electronic device;

FIG. 13 shows an example for explaining an electronic device;

FIG. 14 shows an example for explaining an electronic device;

FIGS. 15A to 15C show examples for explaining an electronic device;

FIG. 16 shows an example for explaining a driving method of anelectronic device;

FIG. 17 shows an example for explaining a driving method of anelectronic device; and

FIG. 18 shows an example for explaining a driving method of anelectronic device.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments will hereinafter be described with reference to drawings.However, the embodiments can be implemented with many different modes.It will be readily appreciated by those skilled in the art that modesand details can be changed in various ways without departing from thespirit and scope of the disclosure.

For enhancing the comfort for a user when holding a tablet-likeelectronic device, this embodiment introduces grips (or grippedportions) to the electronic device by rolling its right and/or leftsides. The use of a foldable electronic device enables such grips to beformed. Using this method, the user can roll one or both of the rightand the left sides to form cylinder-shaped grips that make theelectronic device easy to hold with one or two hands in addition to thenormal tablet usage (tablet mode).

One of possible use cases is holding the electronic device comfortablywith one hand and reading, news or novels on the electronic device whileholding a cup with the other hand (eBook mode). In this mode, theelectronic device may display electronic buttons (software buttons) forminimum operation (page back, forward, and exit, for example) within thereach of fingers or thumb of the hand that holds the electronic device.

Another use case is transformation of the electronic device into ahand-held gaming device, which allows more comfortable and stable gripof the electronic device while playing a game on the electronic device(game mode).

(Supporting Body)

The electronic device may be made by attaching a foldable OLED displayon a supporting body. The supporting body may have a plurality ofchained trapezoid or rectangular columnar bodies. FIGS. 1A to 1C showtransformations of a supporting body 100 corresponding to the abovethree modes. FIG. 1A, FIG. 1B and FIG. 1C show the tablet mode, theeBook mode (the left eBook mode) and the game mode, respectively.

The positions of columnar bodies 101[0] and 101[1] are indicated in FIG.1A, FIG. 1B, and FIG. 1C, among columnar bodies 101. For example, aright grip 102R is formed by rolling the right side of the supportingbody 100, as shown in FIG. 1B. Further, a left grip 102L is formed byrolling also the left side of the supporting body 100, as shown in FIG.1C.

FIG. 2A, FIG. 2B, and FIG. 2C show views from the top, the side and thebottom of the supporting body 100 in the tablet mode, respectively. Asseen, the supporting body 100 includes a plurality of columnar bodies(the columnar bodies 101[0] to 101[10]). Each of the columnar bodies hasa trapezoid or rectangular cross section and some of them may containsome electronic components, such as processors, memories, batteries,sensors (such as gyroscope sensor or accelerometer), speakers,vibrators, microphones and so on.

(Columnar Body)

Each of the columnar bodies 101 has one or more connection portions forlinking to another one or two columnar bodies 101. For example, as shownin FIG. 3A, a columnar body 101[3] has two connection portions, aconnection portion 104 a[3] and a connection portion 104 b[3] on a sidesurface 103 a[3] and a side surface 103 b[3], respectively. Note thatthe side surface 103 a[3] opposes to the side surface 103 b[3].Similarly, a columnar body 101[4] has a connection portion 104 a[4] anda connection portion 104 b[4] on a side surface 103 a[4] and a sidesurface 103 b[4], respectively. Although not shown, the columnar body101[3] has a similar structure with two connection portions at the otherend.

The connection portions 104 a and 104 b have holes 105 a and 105 b,respectively. An axis may be provided through the holes 105 a or 105 bfor linking two columnar bodies 101. For example, the columnar bodies101[3] and 101[4] are linked by the connection portions 104 b[3] and 104a[4] with holes 105 a[4] and 105 b[3] overlapping with each other.

The center of each of the holes 105 a and 105 b may be a rotation axisof the columnar bodies 101 that are linked by the hole. Therefore, forexample, the columnar body 101[3] and the columnar body 101[4] arerotatable around the rotation axis that can be formed in the hole 105a[4] (the hole 105 b[3]). Also, each of the other columnar bodies 101 isrotatable around each of the corresponding rotation axis, and theserotation axes may be substantially parallel to each other.

In the example of FIG. 3A, the connection portions 104 a[3] and 104 b[3]of the columnar body 101[3] is lower than the connection portions 104a[4] and 104 b[4] of the next columnar body 101[4] so that theconnection portion 104 b[3] of the columnar body 101[3] is mechanicallyand/or physically linked to the corresponding connection portion 104a[4] of the columnar body 101[4].

In the example of FIG. 3A, the connection portions 104 a and 104 b ofone columnar body 101 (the connection portions 104 a[3] and 104 b[3] ofthe columnar body 101[3], for example) are provided at the same height.In the example of FIG. 3B, the height of two connection portions 104 aand 104 b of one columnar body 101 is different from each other and theheight of the connection portion 104 a of the one columnar body 101 isthe same as that of the neighboring, columnar bodies 101. It is the samefor the connection portions 104 b.

In the example of FIG. 3C, each of the columnar bodies 101 has two ormore connection portions at one side surface of one end of the columnarbody 101. Although the connection portions 104 a and 104 b are providedat around the upper ends of the columnar bodies 101 in the examples ofFIG. 3A to FIG. 3C, they can be at any place of the columnar bodies 101.

FIG. 4A shows a schematic cross-sectional view of the columnar body101[3] with its major dimensions, i.e., a first length “a”, a secondlength “b”, a height “h”, a side length “x” and a radius “r”. Asdescribed above, the columnar body 101[3] has the holes 105 a[3] and 105b[3]. The radius “r” is a distance between the center of the hole 105a[3] (or the hole 105 b[3]) and the top side of (or a plane thatincludes the top side of) the columnar body 101[3]. The first length “a”is a distance between the centers of the two holes 105 a[3] and 105b[3], and the height “h” is a distance between the center of the hole105 a[3] (or the hole 105 b[3]) and the bottom side of (or a plane thatincludes the bottom side of) the columnar body 101[3]. The side length“x” is equal to the square root of the sum of the square of “h” and thesquare of “(a−b)/2”.

FIG. 4B shows the columnar body 101[3] and the columnar body 101[4] thatare stretched linearly. In this state, the length from the outer edge ofthe columnar body 101[3] to the outer edge of the columnar body 101[4]corresponds to the length from the center of the left hole 105 a[3] tothe center of the right hole 105 b[4], which is “2a”.

FIG. 4C shows the linked columnar bodies 101[3] and 101[4] that arefolded toward the bottom (i.e., folded inside). When folded the most,the columnar body 101[3] and the columnar body 101[4] come into contactwith each other at their bottom corners. The maximum rolling angle θ(unit: radian) is given by “2 arctan((a−b)/2h)”.

This restricts the rolling of the supporting body 100 as the columnarbodies 101 naturally stop the supporting body 100 from rolling further.Furthermore, using such shaped columnar bodies 101 also sets the minimumradius of the rolled side of the supporting body 100, which makes iteasier for the user to hold firmly the formed grip. Smaller columnarbodies 101 can be used in order to make the grips rounder.

By folding, the length from the outer edge of the columnar body 101[3]to the outer edge of the columnar body 101[4] is extended to “2a+rθ” asshown in FIG. 4C. This means that an extra length “rθ” is needed inorder to fold the columnar bodies 101[3] and 101[4]. And the smaller “r”brings the shorter extended length. Ideally, if “r” is zero, theextended length is also zero.

In the above-described manner, each of the columnar bodies 101 ismechanically and/or physically linked with one or two neighboring,columnar bodies 101 and rotatable around one or two axes. Further, thesupporting body 100 is designed such that rolling at least one of theright side and the left side of the supporting body 100 forms the grip102R or the grip 102L by rotating some of the columnar bodies 101 aroundthe corresponding axes.

(Stop)

Since the electronic device should not be folded toward the top, i.e.the electronic device should be foldable only toward the bottom (orinside); the columnar bodies 101 can be provided with stops 106 thatprevent this undesired transformation, as shown in FIG. 5A.

FIG. 5B shows the columnar body 101[3] and the columnar body 101[4] eachhaving the stop 106 that are linked linearly. It is difficult or ratherimpossible to fold them towards the top without destroying the stops106.

FIG. 5C shows the linked columnar bodies 101[3] and 101[4] that arefolded toward inside. It is easy to transform the linked columnar bodies101[3] and 101[4] from the state shown in FIG. 5B to the state shown inFIG. 5C.

Since the stop 106 protrudes outside of the columnar bodies 101[3] and101[4] when the columnar bodies 101[3] and 101[4] are folded (see FIG.5C), the stops 106 may be provided so as not to overlap with theflexible display that is formed over the columnar bodies 101.

FIG. 5D shows another example. The columnar bodies 101[3], 101[4], and101[5] have stops 107[3], 107[4] and 107[5], respectively. The stops107[3] and 107[4] are designed to be stored within hollows 108[4] and108[5] formed in the columnar bodies 101[4] and 101[5], respectively.

In FIG. 5D, the columnar bodies 101[4] and 101[5] are straight. Even ifthe user tries to fold the columnar body 101[5] upward (fold outside),the stop 107[4] blocks the bottom wall of the hollow 108[5] that isgoing up.

It should be noted that the stop 107 can also restrict inside folding.As shown in FIG. 5D, the columnar body 101[3] is folded downward (foldedinside). There is a space between the right bottom corner of thecolumnar body 101[3] and the left bottom corner of the columnar body101[4]. A further downward folding of the columnar body 101[3], however,is prevented because the stop 107[3] is blocked by the upper wall of thehollow 108[4].

The inner wall of the hollow 108[4] is designed to be outside of thelocus that is formed in accordance with the motion (rotation) of the tipof the stop 107[3]. The hollow 108[4] may be substantially closedbetween the columnar bodies 101[3] and 101[4], and the stop 107[3]substantially moves inside of the hollow 108[4]. Therefore, theunevenness caused by folding the columnar bodies 101 is smaller in FIG.5D than in FIG. 5C.

(Locking Plate)

During the tablet mode, the electronic device should be rigidlystraight. The tablet mode can be enhanced by introducing a locking platemechanism in the electronic device. A sliding locking plate (or layer,rod, body or the like) made of a rigid material that is built in theelectronic device may be used for this purpose. Sliding this into thecolumnar bodies 101 locks the columnar bodies 101 into a rigid position,and makes the electronic device usable as a regular tablet.

FIGS. 6A to 6D show an example of the locking plate. A locking plate109[0] is designed such that it is stored in a hollow or hole in thecolumnar body 101[0] (FIG. 6A) and slides outside (FIG. 6B).

FIG. 6C shows a schematic cross-sectional view of the supporting body100 folded inside. The locking plate 109[0] is stored in the hollow ofthe columnar body 101[0]. Further, a hollow is formed in each of theother columnar bodies 101[1] to 101[5].

FIG. 6D shows a schematic cross-sectional view of the supporting body100 in the tablet mode. The locking plate 109[0] slides through thehollows of the columnar bodies 101[5], 101[4], 101[3] and so on torigidly straighten the supporting body 100.

FIGS. 7A to 7D show another example of the locking plate. A lockingplate 109 is designed such that it is stored in a hollow or hole in eachof the columnar bodies 101 (FIG. 7A) and slides (FIG. 7B) to anotherhollow or hole in the neighboring one or more columnar bodies 101.

FIG. 7C shows a schematic cross-sectional view of the supporting body100 folded inside. Each of the locking plates 109 is stored in thehollow of each columnar body 101. In this example, the columnar body101[0] is not equipped with any locking plate, although a hollow isprovided therein.

FIG. 7D shows a schematic cross-sectional view of the supporting body100 in the tablet mode. Each of the locking plates 109 slides to thehollow of the next columnar body 101. For example, a locking plate109[3] that has been stored in the hollow of the columnar body 101[3] inFIG. 7C slides to the hollow of the columnar body 101[4], and bridgesthe columnar body 101[3] and the columnar body 101[4].

The motion of the locking plates 109 may be electrically and/ormechanically controlled. For example, the locking plates 109 may bedesigned to move while sensing the angle between two neighboringcolumnar bodies 101. Alternatively, the locking plates 109 may bedesigned to move while sensing some pressure to the columnar bodies 101.

(Spring or Elastic Material)

Using springs or elastic materials is also effective. FIGS. 8A to 8Cshow examples of implementing springs or elastic materials into theelectronic device. Introducing them enhances the feel of the electronicdevice as it does not feel limp and gives certain resistance to theuser's grip.

This function can be implemented by putting a spring between twocolumnar bodies 101 to push them apart (i.e. toward outside). It isimportant in one example that the spring is used in combination with astop that prevents the columnar bodies 101 from rolling toward outside.

FIG. 8A is a schematic view of the columnar bodies 101[3] and 101[4] anda spring 110 between them. FIG. 8B is a perspective view. In thisexample, one end of the spring 110 is fixed to the columnar body 101[3]and the other end is fixed to the columnar body 101[4]. In this example,the axis of the spiral of the spring 110 is parallel to the rotationaxis of the columnar bodies 101[3] and 101[4], but one embodiment of thepresent invention is not limited thereto.

The function of a spring can also be implemented by positioning anelastic material (such as rubber, silicone resin, and so on) in theelectronic device. For example, two layers (or rods, plates, bodies orthe like) of the elastic material are provided to sandwich the rotationaxes of the columnar bodies 101. FIG. 8C shows an example using anelastic material layer 112 and an elastic material layer 113, in whichexample the electronic device is flattened when there is no forceapplied thereto. The elastic material layer 113 can be provided throughthe columnar bodies 101.

(Other Equipment)

Furthermore, (part of) the supporting body 100 may be designed to workas a physical button. For example, the physical button can beimplemented by incorporating a pressure sensor into the columnar body101 and measuring the mechanical stress that the columnar body 101 isaffected by when the user holds the electronic device. The pressuresensor may be made using piezo resistors, for example. The columnarbodies 101 can be made of a more elastic (rubber-like) material thatallows a more distinctive springy feel when the user holds the grip.

Further, one or more mechanical buttons may be provided between twocolumnar bodies 101 so that the user feels a real pressing.

The above explained techniques, such as stops, locking plates, andsprings, can be combined with each other to obtain more preferableresults.

(Electronic Device 1)

The electronic device is made by mounting a flexible display over thesupporting body 100 described above. FIG. 9A shows an electronic device114 a in the eBook mode. The electronic device 114 a includes thesupporting body and a flexible display 115. As explained above, thesupporting body may include the columnar bodies 101[0] to 101[10] linkedtogether.

FIG. 9B shows a schematic cross-sectional view of the electronic device114 a. The flexible display 115 may include a flexible layer 115 a, adevice layer 115 b, and a flexible layer 115 c, as shown in FIG. 9C. Thedevice layer 115 b is located between the flexible layer 115 a and theflexible layer 115 c in this example. The flexible layer 115 c that isprovided between the columnar bodies 101 and the flexible layer 115 amay be thinner than the flexible layer 115 a. Further, a layercontaining capacitive or optical touch sensors may be provided in theflexible display 115 in order to enable a multi-touch function. Thefunction of the touch sensors may be provided in the device layer 115 b.

As described with reference to FIG. 4C, the extended length that isproportional to the rotational radius “r” is needed for thecircumference of the supporting body when the supporting body is folded.Therefore, some mechanical structure may be added for supplying theextended length.

For this purpose, the flexible display 115 may be placed without beingfixed to any of the columnar bodies 101 or any of the columnar bodies101 except the columnar body 101[0]. For example, the portions of theflexible display 115 corresponding to the columnar bodies 101[1] to101[10] may be designed to move in accordance with the degree offolding.

(Electronic Device 2)

FIG. 10A shows another electronic device 114 b in the eBook mode. Theelectronic device 114 b includes columnar bodies 111[0] to 111[10] andthe flexible display 115. In this example, the columnar bodies 111[0] to111[10] are not directly linked together. The columnar bodies 111[0] to111[10] are attached to the flexible display 115. Thus, the columnarbodies 111 are linked via the flexible display 115.

FIG. 10B shows a schematic cross-sectional view of the electronic device114 b. The flexible display 115 may include a flexible layer 115 a, adevice layer 115 b, and a flexible layer 115 c, as shown in FIG. 10C,and the columnar bodies 111 are attached to the flexible layer 115 c atintervals of “W” that may decide the radius of curvature between thecolumnar bodies 111. In the electronic device 114 b, the radius “r” maybe minimized because it does not need mechanical linking. One or both ofthe flexible layer 115 a and the flexible layer 115 c may be made ofsome elastic material such as silicone resin or rubber.

Some techniques explained above, such as stops, locking plates, andsprings, can be used in the electronic device 114 b. For example, stopsare effective for limiting the extreme folding, but not for fixing andmaintaining the shape. However, with use of the stops in combinationwith springs or locking plates, the electronic device 114 b can bestraightened in its standard form while it can be folded (rolled)moderately.

(Tablet Mode)

FIG. 11 shows the electronic device 114 b in the tablet mode as anexample. When the electronic device 114 b is unfolded and straightenedout, it is used as a regular tablet device. The locking plates can beused in order to make the electronic device 114 b sufficiently rigidwhen used in the tablet mode.

Most parts of the flexible display 115 is usable as a main display area116 in the tablet mode. Specifically, the width of the main display area116 is called “Full Width” and the width corresponding to each columnarbody 111 is called “Unit Width”.

It should be noted that, for example, the portion of the flexibledisplay 115 corresponding to the columnar body 111[5] does not alwaysmean the portion overlapping with the columnar body 111[5].

Although the periphery of the main display area 116 contains touchsensors, they may be configured to be inactive for avoiding unnecessaryreactions by the user's hand.

(eBook Mode)

FIG. 12 shows the electronic device 114 b in the eBook mode as anexample. Specifically, this state is called “left eBook mode” becausethe columnar bodies 111[6] to 111[10] are folded and the right portionof the flexible display 115 is not used as the main display area 116.The folded columnar bodies 111[6] to 111[10] can be used as a grip 102Rfor holding the electronic device 114 b.

When only one of the right and the left sides is folded, the electronicdevice 114 b can enter the eBook mode. In this mode, the main displayarea 116 is used to show some information (text, image and/or video, forexample), and the grip 102R provides a stable and comfortable hold ofthe electronic device while reading the information.

In the eBook mode, the left and the center portions of the flexibledisplay 115 are used as the main display area 116. Therefore, the widthof the main display area 116 is smaller than that in the tablet mode.For example, the width may be smaller than “Full Width” by five times“Unit Width”. Similarly to the tablet mode, the touch sensors at theoutside of the main display area 116 may be configured to be inactive.

As shown in FIG. 13, the grip 102R can be used as a sub display area 117displaying non-intrusive interface such as next- and previous-pagebuttons, an exit button, etc. In this case, the touch sensors in the subdisplay area 117 may be configured to be selectively active.

Furthermore, when using the physical button described above, the grip102R can be used for navigating the document. For example, it may beconfigured that a single grasp executes the operation of proceeding tothe next page and double grasps execute the operation of going back tothe previous page.

(Game Mode)

FIG. 14 shows the electronic device 114 b in the game mode as anexample. When both of the right and the left sides of the electronicdevice 114 b are rolled, the electronic device 114 b decides to enterthe game mode. In this mode, for example, the upper half portion of themain display area 116 can be used for the video or object displaywindow, and the bottom half portion of the main display area 116 can beused for displaying the game controls.

The columnar bodies 111[1] to 111[5] and 111[6] to 111[10] are foldedand only the center portion of the flexible display 115 is used as themain display area 116. Therefore, the width of the main display area 116is much smaller than that in the tablet mode. For example, the width maybe smaller than “Full Width” by 10 times “Unit Width”. The foldedcolumnar bodies 111[1] to 111[5] and the folded columnar bodies 111[6]to 111[10] can be used as a grip 102L and a grip 102R, respectively, forholding the electronic device 114 b.

Since the folded portions of the flexible display 115 include the touchsensors, they can also show additional controller buttons in the subdisplay areas 117 in the grips 102L and 102R, as described in the eBookmode, or with reference to FIG. 13. Note that the sub display areas 117may be provided in both grips 102L and 102R that are the rolled portionsof the electronic device 114 b. As described above, physical buttons mayalso work at the grips 102L and 102R.

In another example, the whole or most of the main display area 116 isused for the video or object display window. This means that neithercontroller nor button is shown in the main display area 116. In acar-racing game, for example, the grips 102L and 102R held by the usercould be used for steering, an embedded gyroscope sensor could be usedto sense the rotation of the steering, and the buttons provided in thegrips 102L and 102R could be used for acceleration and deceleration. Noother display may be needed in the main display area 116. Larger area ofthe main display area 116 can be used for showing the game because of noextra input buttons displayed.

Some modifications are applicable. For example, it is possible to usethe electronic device while folding only the link portions of thecolumnar bodies 111[2] to 111[4]. In this case, the portion of theflexible display 115 corresponding to the columnar bodies 111[0] and111[5] to 111[10] can be used as a display, which is a modified righteBook mode.

The above examples are explained using the electronic device 114 b ofFIGS. 10A to 10C; however, they are applicable also to the electronicdevice 114 a of FIGS. 9A to 9C.

(Sensor)

As described above, for the electronic device 114 a (or the electronicdevice 114 b), the main display area 116, the active touch sensors areaand/or the sub display area 117 needs to be adjusted in accordance withthe degree of folding (rolling). The folding can be sensed by a varietyof sensors.

For example, conducting materials 118 a and 118 b can be integrated onthe upper right and left corners of each columnar body 101,respectively, as seen in FIG. 15A.

Since the columnar bodies 101 are linked, a pair of the conductivematerial 118 a of one columnar body 101 and the conductive material 118b of the next columnar body 101 forms a resistive sensor. For example, aconductive material 118 b[3] and a conductive material 118 a[4] form asensor 120[3], as seen in FIG. 15B. The sensor 120[3] corresponds to thelink portion 119[3].

When the columnar bodies 101 are folded to touch each other at theircorners, the conductive materials 118 a and 118 b adjacent to each otherare also brought into contact to flow current. Therefore, it is decidedthat the corresponding link portion 119 is sufficiently folded. In FIG.15C, it is decided that all of the link portions 119[1] to 119[5] aresufficiently folded because the corresponding sensors 120[1] to 120[5]are conductive.

Note that other types of sensors than the resistive sensor, such aspressure sensors, capacitive sensors, magnetic sensors or opticalsensors, can be used for sensing the degree of folding or the anglebetween the neighboring columnar bodies 101.

Although not shown in FIG. 15C, a sensor 120[6] is provided between thecolumnar body 101[0] and the columnar body 101[6]. Similarly, sensors120[7] to 120[10] are provided, and the sensors 120[6], 120[7], 120[8],120[9], and 120[10] correspond to link portions 119[6], 119[7], 119[8],119[9], and 119[10], respectively.

(Mode Decision Process)

The sensors 120 can be used to automatically decide which mode the useris to make the electronic device enter. FIG. 16 shows an example of aflow chart of deciding the mode.

First, it is tested whether both of the link portion 119[5] and the linkportion 119[6] are folded or not. If Yes, the electronic device 114 aenters the game mode. If No, it is tested whether the link portion119[5] is folded or not. If Yes, the electronic device 114 a enters theright eBook mode (R-eBook mode). If No, it is tested whether the linkportion 119[6] is folded or not. If Yes, the electronic device 114 aenters the left eBook mode (L-eBook mode). If No, the electronic device114 a enters the tablet mode. The main display area 116 is resized inaccordance with the decided mode.

FIG. 17 shows another example. The flow chart shown in FIG. 17 can beused for changing the main display area 116 in accordance with thefolded portion. First, “L” is set to 0 and “i” is set to 1. Then, it istested whether the link portion 119[i] is folded or not (firstquestion). If Yes, “L” is set to “i” (i.e., at the first loop, “L” isset to 1). Further, regardless of the answer to the first question, “i”is increased by 1. Then, it is tested whether “i” is larger than thenumber of link portions at the left side of the electronic device(second question). In the electronic device 114 a, the number is 5. IfNo, it goes back to the first question. If Yes, an unusable left widththat is not usable as the main display area 116 is calculated as aproduct of “L” and “Unit Width”.

For example, in the case where the link portions 119[1], 119[3], and119[4] are folded, the flow chart of FIG. 17 decides that “L” is fourand the unusable left width is four times “Unit Width”, so that theportion corresponding to the columnar body 101[5] is usable as the maindisplay area 116 while the portion corresponding to the columnar bodies101[1] to 101[4] is not used even though the link portion 119[2] is notfolded.

The flow chart of FIG. 17 can decide only the left side of the maindisplay area 116. The right side can be decided by the flow chart ofFIG. 18. The process of FIG. 18 is similar to that of FIG. 17, and theunusable right width that is not usable as the main display area 116 iscalculated similarly.

Accordingly, the width of the main display area 116 is decided bysubtracting the unusable right width and the unusable left width from“Full Width”.

The calculation may be varied in accordance with the decided mode. Forexample, “L” or “R” directly obtained from the flow charts of FIG. 17and FIG. 18 is used for calculating the width of the main display area116 in the eBook mode, while the unusable right width (or the unusableleft width) is defined as the product of “L−1” (or “R−1”) and “UnitWidth” in the game mode.

REFERENCE NUMERALS

-   100: supporting body, 101: columnar body, 102R: grip, 102L: grip,    103 a: side surface, 103 b: side surface, 104 a: connection portion,    104 b: connection portion, 105 a: hole, 105 b: hole, 106: stop, 107:    stop, 108: hollow, 109: locking plate, 110: spring, 111: columnar    body, 112: elastic material layer, 113: elastic material layer, 114    a: electronic device, 114 b: electronic device, 115: flexible    display, 115 a: flexible layer, 115 b: device layer, 115 c: flexible    layer, 116: main display area, 117: sub display area, 118 a:    conducting material, 118 b: conducting material, 119: link portion,    120: sensor

This application is based on Japanese Patent Application serial no.2014-095610 filed with Japan Patent Office on May 6, 2014, the entirecontents of which are hereby incorporated by reference.

1. (canceled)
 2. An electronic device comprising: a flexible display;and a plurality of columnar bodies, the plurality of columnar bodiescomprising a first columnar body and a second columnar body, wherein awidth of the first columnar body is larger than a width of the secondcolumnar body, wherein each of the plurality of columnar bodies islinked with neighboring one or two of the columnar bodies at a linkportion and rotatable around an axis at the link portion, wherein theflexible display is designed to change its shape in accordance with ashape formed by the plurality of columnar bodies, wherein a curvedsurface is formed in the flexible display by rotating the plurality ofcolumnar bodies around the axes at the link portions, wherein theflexible display is placed without being fixed to the plurality ofcolumnar bodies.
 3. The electronic device according to claim 2, whereina portion of the flexible display corresponding to the plurality ofcolumnar bodies is designed to move in accordance with folding.
 4. Theelectronic device according to claim 2, wherein a thickness of theflexible display is smaller than a thickness of the plurality ofcolumnar bodies.
 5. The electronic device according to claim 2, whereinthe flexible display is configured to be bent outwards.
 6. An electronicdevice comprising: a flexible display; and a plurality of columnarbodies, wherein in a bended state, a first part of the flexible displayoverlaps with a second part of the flexible display, wherein each of theplurality of columnar bodies is linked with neighboring one or two ofthe columnar bodies at a link portion and rotatable around an axis atthe link portion, wherein the flexible display is designed to change itsshape in accordance with a shape formed by the plurality of columnarbodies, wherein a curved surface is formed in the flexible display byrotating the plurality of columnar bodies around the axes at the linkportions, wherein the flexible display is placed without being fixed tothe plurality of columnar bodies.
 7. The electronic device according toclaim 6, wherein a portion of the flexible display corresponding to theplurality of columnar bodies is designed to move in accordance withfolding.
 8. The electronic device according to claim 6, wherein athickness of the flexible display is smaller than a thickness of theplurality of columnar bodies.
 9. The electronic device according toclaim 6, wherein the flexible display is configured to be bent outwards.